Data entry dependent on drop down option

Hello everyone

This is my first post here. In my spreadsheet I have column C with a "Yes" or "No" drop down. I want column D to do 3 things. 1- If Yes to allow a 6 digit number. 2- If No to restrict all entries. 3- If C is blank then restrict all entries

What I basically want to do if cell A11 is populated (it has a different drop down Menu listing location) then allow entry in C11 and if C11 is populated, then allow entry in D11, if D11 is populated then allow entry in E11 and so on. I have been trying to do all this with formulas alone but its not doing it. I have never worked with VBA. I am fairly comfortable with formulas though.

HELP!!!!

Thank you all,
Gaby

Hello Gaby welcome to the forum.

Not sure if you're still looking for a solution here but see the attached example. I've applied some Custom Data validation based on your description. Does this do as you require?

DBY