Step 1: Make sure you have the shop manual for your bike.
Step 2: Read both the brake sections and ABS sections so that you have a general understanding of operation and component locations.
Step 3: Check the operation and condition of your service brakes before you attend to the ABS system.
In the ABS section of my factory '14 Suzuki DL1000 Service manual there are 41 pages of descriptions, schematics, pictorials, inspections, and test + service procedures. Some require special tools and equipment.
BUT...There is shown a special service tool Suzuki 09930-82760 that plugs into the mode select coupler under the seat to read diagnostic trouble codes which are then flashed on the instrument cluster's ABS indicator lamp.
I havent looked for this coupler on my own Vstrom, but if it's similar to the mode select switch tool, a simple paper clip might accomplish the same thing. I bought the Suzuki tool for Mode select off Amazon for $17, makes setting TPSs simple and quick.
Realize you have wiring, sensors, connectors, fuses, relays, switches, etc in the system. Get the manual and familiarize yourself with your machine.