I couldn't find any manual for that amp, but I did find an old photo that shows the VHF input at the right end that you did not include in your photo.
Your strongest channels are UHF, so just connect the antenna coax to the UHF input.
If you also want to try for the weak VHF channels, then connect the antenna coax to the common port of a UVSJ, connect the VHF port of the UVSJ to the VHF input of the amp, and connect the UHF port of the UVSJ to the UHF input of the amp.