Pilot drill holes into desktop. Screw legs into desktop. X4 per drawer, one leg per corner of drawer. Place desktop onto drawers. Align desktop. Mark leg placement. Remove desktop.

Using this:

3M Scotch 4910 VHB Tape: 1 in. x 15 ft. (Clear) https://www.amazon.com/dp/B00I4E4NE8/ref=cm_sw_r_apan_i_NB623JJRG7VVVVKK31WC?_encoding=UTF8&psc=1

Cut pieces of VHB Tape and place on bottoms of legs. Where you marked leg placement, is where you'll carefully set legs onto. Press and hold for a minute.

Done.