Need a little help - have the following parts my son is assembling.

Tamiya Grasshopper
Futaba 3PRKA 2.6G FHSS transmitter R203GF
Tamiya TEU-105BK Brushed ESC

Components wired as instructed. Have reset linking. Good control for steering. Red light still blinking & no throttle control.

I can connect the throttle wires to the steering connect point and then have throttle control but lose steering.

Any suggestions? ESC has 4 potential connections - B, 1 (steering), 2, 3, 4

Would be great to get any help vs just returning the ESC - unless that's what need to happen

Thanks in advance!!