How to make minecraft-like slab?

slab class:

package net.mcreator.travelers_dream_blocks;

import net.minecraftforge.oredict.OreDictionary;
import net.minecraftforge.fml.relauncher.SideOnly;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.common.registry.GameRegistry;
import net.minecraftforge.fml.common.event.FMLInitializationEvent;
import net.minecraftforge.client.model.ModelLoader;
import net.minecraftforge.client.event.ModelRegistryEvent;

import net.minecraft.world.World;
import net.minecraft.world.IBlockAccess;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.AxisAlignedBB;
import net.minecraft.util.EnumFacing;
import net.minecraft.util.BlockRenderLayer;
import net.minecraft.item.ItemBlock;
import net.minecraft.item.Item;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.entity.EntityLivingBase;
import net.minecraft.client.renderer.block.model.ModelResourceLocation;
import net.minecraft.block.state.IBlockState;
import net.minecraft.block.properties.PropertyDirection;
import net.minecraft.block.properties.IProperty;
import net.minecraft.block.material.Material;
import net.minecraft.block.SoundType;
import net.minecraft.block.BlockDirectional;
import net.minecraft.block.Block;
import net.minecraft.block.BlockSlab;


@Elementstravelers_dream_blocks.ModElement.Tag
public class MCreatorSlabAlter extends Elementstravelers_dream_blocks.ModElement {
	@GameRegistry.ObjectHolder("travelers_dream_blocks:slabalter")
	public static final Block block = null;

	public MCreatorSlabAlter(Elementstravelers_dream_blocks instance) {
		super(instance, 19);
	}

	@Override
	public void initElements() {
		elements.blocks.add(() -> new BlockCustom());
		elements.items.add(() -> new ItemBlock(block).setRegistryName(block.getRegistryName()));
	}

	@Override
	public void init(FMLInitializationEvent event) {
		OreDictionary.registerOre("slabWood", block);
	}

	@SideOnly(Side.CLIENT)
	@Override
	public void registerModels(ModelRegistryEvent event) {
		ModelLoader.setCustomModelResourceLocation(Item.getItemFromBlock(block), 0, new ModelResourceLocation("travelers_dream_blocks:slabalter",
				"inventory"));
	}

	public static class BlockCustom extends BlockSlab {
		public static final PropertyDirection FACING = BlockDirectional.FACING;

		public BlockCustom() {
			super(Material.WOOD);
			setRegistryName("slabalter");
			setUnlocalizedName("slabalter");
			setSoundType(SoundType.WOOD);
			setHarvestLevel("axe", 1);
			setHardness(2F);
			setResistance(15F);
			setLightLevel(0F);
			setLightOpacity(0);
			setCreativeTab(MCreatorTravelersDream.tab);
			this.setDefaultState(this.blockState.getBaseState().withProperty(FACING, EnumFacing.SOUTH));
		}

		@SideOnly(Side.CLIENT)
		@Override
		public BlockRenderLayer getBlockLayer() {
			return BlockRenderLayer.CUTOUT_MIPPED;
		}

		@Override
		public boolean isFullCube(IBlockState state) {
			return false;
		}

		@Override
		public AxisAlignedBB getBoundingBox(IBlockState state, IBlockAccess source, BlockPos pos) {
			switch ((EnumFacing) state.getValue(BlockDirectional.FACING)) {
				case SOUTH :
				default :
					return new AxisAlignedBB(1D, 0D, 1D, 0D, 0.5D, 0D);
				case NORTH :
					return new AxisAlignedBB(0D, 0D, 0D, 1D, 0.5D, 1D);
				case WEST :
					return new AxisAlignedBB(0D, 0D, 1D, 1D, 0.5D, 0D);
				case EAST :
					return new AxisAlignedBB(1D, 0D, 0D, 0D, 0.5D, 1D);
				case UP :
					return new AxisAlignedBB(0D, 1D, 0D, 1D, 0D, 0.5D);
				case DOWN :
					return new AxisAlignedBB(0D, 0D, 1D, 1D, 1D, 0.5D);
			}
		}

		@Override
		protected net.minecraft.block.state.BlockStateContainer createBlockState() {
			return new net.minecraft.block.state.BlockStateContainer(this, new IProperty[]{FACING});
		}

		@Override
		public IBlockState getStateFromMeta(int meta) {
			return this.getDefaultState().withProperty(FACING, EnumFacing.getFront(meta));
		}

		@Override
		public int getMetaFromState(IBlockState state) {
			return ((EnumFacing) state.getValue(FACING)).getIndex();
		}

		@Override
		public IBlockState getStateForPlacement(World worldIn, BlockPos pos, EnumFacing facing, float hitX, float hitY, float hitZ, int meta,
				EntityLivingBase placer) {
			if (facing == EnumFacing.WEST || facing == EnumFacing.EAST)
				facing = EnumFacing.UP;
			else if (facing == EnumFacing.NORTH || facing == EnumFacing.SOUTH)
				facing = EnumFacing.EAST;
			else
				facing = EnumFacing.SOUTH;
			return this.getDefaultState().withProperty(FACING, facing);
		}

		@Override
		public boolean isOpaqueCube(IBlockState state) {
			return false;
		}

		@Override
		public boolean isFlammable(IBlockAccess blockAccess, BlockPos pos, EnumFacing face) {
			return true;
		}

		@Override
		public boolean canSilkHarvest(World world, BlockPos pos, IBlockState state, EntityPlayer player) {
			return false;
		}
	}
}

* that class is after adding import and extending BlockSlab, but before any other changes, which I did without any understanding))

Thank you for the reply!