Struggling with hot water and electrics blown

Hi all we are complete novices and having trouble with the setting up. We are trying everything it before we go away for first time next week. 

We filked our Aqua toll connected pump and plugged ehu in. All seemed ok switched pump switch on in can turned water tap on furthest from tank but water doesn't seem to get very hot?? Do we need to leave it for s while to heat.  We have 2 switches next to pump switch that says 1kw and 2kw do I need these on or is this for the heating ?? 

Also wanted to check fridge over but have 3 settings ac dc and gas I chose ac but after 10 mins all electric suddenly went off and a tick tick sound came from under front bunk we checked fuses and fridge one had melted it says it should be a 15 but had a 20 in it could this be the iron or did I have it on ering setting now taken fuse out all together and electric gas come in but water still not very hot u fact seems to go colder after a couple of mins.

sorry for long winded post and that we sound thick but we are complete novices to caravanning

tganks in advance for your help