As usual, appreciate if anyone can help with this one please

Checked previous threads, but didn't find anything that quite matched this one

Engine is a 1.9 diesel, 1Y (85 van, Seat engine though!). Have got 5 bar VDO gauge and MK1 Golf sender that I'm going to put in place of existing hi pressure switch on the oil filter housing.
Just not sure what connects to what though?

a '+' (with 144 written below it?), something that looks like a G and the final one which looks like an upside down 'T' - assume that's the earth maybe?
If anyone's been and done this one, would appreciate any help with what bit goes to what please. PS. Do I need an inline fuse too?
Thanks a lot.
Brian