Welcome
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I think an ackie would be a great choice. I personally don't have one (I keep bosc monitors) but they are one of the best monitors to start out with mainly due to their small size and housing requirements.
Minimum enclosure size would be a 4 x 2 x 4 wooden box with front opening doors (fully sealed with no vents or screen). I personally feel this is too small as they are a very active species and would recommend at least a 5 x 3 x 4 (bigger is always better).
For substrate you want a sand/ soil mixture (usually top soil and play sand), firmly packed down as if you've walked on it, and at least 12 inches deep.
A basking spot can be created using halogen flood lights (PAR38)- either one or two bulbs are needed depending on the length of the monitor. You want the basking spot to cover at least the snout to vent length. To measure the basking temperature you'll need an IR Temperature Gun to read the surface temperature. Aim for between 130-150F. The lights need to be mounted inside the enclosure.
For measuring ambient temperatures and humidity you'll need a digital thermometer and hygrometer. The lowest ambient temperature should be between 75-80F and the humidity above ground should be between 60-80%.
For furnishings it's completely up to you. Alot of people use braches/ logs, leaf litter, shelves, rocks, etc. Just make sure anything that goes into the enclosure is properly secured against movement if it's heavy enough to pose a risk of injury. These guys would be the equivalent of a bearded dragon on speed and monitors generally love to destroy enclosure decorations
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