How should I go about to remove a glue down wood floor? on concrete slab.

Really depends on how well it's down. Is it parque or plank ? Usually for me it's the old hammer and crow bar. Then I take it from there. If it's plank down really tight , I will use a circular saw and set the blade the thickness of the wood, then cut planks into smaller pieces, like a grid. Then I use one of three methods, either the hammer and crow bar, a skid ( Heavy 6' bar with a blade on the end ), or I use my Hilti TE-505 ( you can rent at HD ). Cross your fingers, if the floor was laid in the old LP Adhesive, the adhesive will be crystalized and the planks may come up without cutting, and removal is easier. Again depending on how it's down. Once the wood is up I go over the slab with a razor scraper and remove the adhesive.