Combine 2 data sets into one list based on user selection in drop downs.

Good Morning,
Pulling my hair out. I have 2 sets of data on 2 tabs that I need to combine based on user selection in 2 drop downs. I have a tab ("DO NOT ALTER") sort of working with a HLOOKUP for one column. I need it now to bring in data ("Qty) in the next column based on the result of the first column. I've included my spreadsheet which has notes. If you can actually help and get all the data to combine into one pretty equipment list that would be awesome.
Thanks for any help.
Cindy

martindwilson
Thank you for taking a look. It must be a compatability issue. It isn't erroring on my spreadsheet. The "#REF" is $1:$100000. That is the formula I have working. I'm looking for a formula to drop in the corresponding qty in the next column.
Cindy

Thank you popipipo but that is not the formula I need help on. I actually need help with populating the "qty" column next to the "items needed" column. It needs to go find the qty from the appropriate tab and return it based on the results in "Items needed" column. I have no idea what kind of formula to use which is why it is blank.
Cindy

That is GREAT! I tried to copy the formula into "DO NOT ALTER" B3 and changed it like this =IF(A3=0,"",VLOOKUP(A3,INDIRECT('Lab Request'!$B$7),2,0)) to get that qty column working but it is giving me an error and I don't know why. Can you give one last bit of help? Thanks so much!

Fabulous. Thank you so much for your help!