How to make something like "Is block at xyz (block name)" in procedure system?

First under the Logic and Loops tab grab a "If___, Do___" box. Everything I'm going to have you grab is going to be in the If slot. Whatever you want it do whenever the block is there put in the Do slot. Next, you will need to grab a "____ == ____" box from the Logic Operations tab, and it will need to have a block symbol on it. Third, you will need it grab a "Get Block at X: Y: Z:" box from the block actions tab, it will go in the first blank from the green "____ == ____" box. Finally, you will need to put a box that contains only a grey square and the block symbol on it. It can be found in the Minecraft Components tab. To select what block you want to be at the coordinates simply click on the grey square. 

It should look a little like this: https://www.pylo.co/static/mcreator/procedures/checkBlockBelow.gif

Hope this helps!

Put the "not" block in between the "if" and the "block == block"