There are a few AGM telecom battery users on this Forum. I have a bank of three smaller ones that total 100AH of capacity. They can be used just like any other battery solution. The Mfg of your brand should have charge instructions available.
FWIW, I charge mine with solar and have them connected in parallel to a bank of 6V GC2 batteries. The charge controller does all of the heavy lifting. I monitor voltages and, for the FLA batteries, add water and monitor their chemistry using a hydrometer. That is about the only downside to AGM, IMO. I'm not able to accurately measure the cell capacities.