I had to do this for the first time recently and was very worried about it and tried to remember the pig keeping course when they made it look so easy.
They said give them some food and do it while they are eating but as mine was off her food it wasn't an option so OH grabbed the back legs and lifted her up, wheelbarrow style then I did the deed. Actually it was easy. We needed to call the vet out and she also took the temperature with OH doing the wheelbarrow trick again.
Sally