I know how to do the whole thing and replace fuel filter etc.

However i cant remember what to do once i have put new oil into the car. Do i crank the engine and let the oil move about?

Last time i did i remembered not starting the car straight away..

Ta

Last time I did my Astra, I de-fused the fuel pump and just cranked it until the oil light went out and pressure came up

I would suggest just starting the car as normal and let the engine do the rest so-to-speak.

Unless you've washed all the oil from the sufaces of the inner components with a flush there is enough of an oil film to let the sump of oil rise normally., It's pretty much the same as when starting for the frist time overnight etc.

change the oil, refil to just below max mark and then start up the car and let idle for a minute or so, turn off and recheck engine oil and adjust to maximum mark