The Siemens 3RV2411-1HA10-0BA0 is a SIRIUS-brand circuit breaker specifically designed for transformer protection, not general motor or cable protection. Mount it any position you like; screw and snap-on both work.
That's the key difference from a general-purpose motor-protective breaker (Class 10 is standard for motor starting too, but the curve here is tuned for transformer inrush). The interrupting ratings tell you what fault current it can safely clear: 100 kA at 400 V AC, 42 kA at 500 V AC, and 6 kA at 690 V AC. At 240 V AC it still holds 100 kA.
The screw terminals accept 2× (0.75 to 2.5 mm²) solid or stranded, or 2× 4 mm². Use a Pozidriv size 2 tip with a 5 to 6 mm shaft diameter. Clearance distances: 50 mm upwards and downwards, 30 mm at the sides, zero forwards and backwards. That means you can butt it against the back panel and the door — no extra breathing space needed behind the rail.