Williams told the Evening Post "It's nice to play in the pressure games
"And fair play to us, we always seem to turn it on as a team when it's needed. When the cameras have been watching us this season or it has been a particularly big game, we have nearly always produced a performance this season.
"We have done it when it has mattered and now we have to do that again in one more game.
"We go into Reading knowing that's all it takes — we are 90 minutes away from the Premier League.
"It's a brilliant feeling to be going to Wembley," he admitted.
"I have never been involved in anything like this before and I am just trying to enjoy every minute and take it all in.
"Going to Wembley will be great for the whole city. Everyone can have a good day out and hopefully we can win the game and put this club even more on the map.
"Forest was an incredible game, I've never played in one like it," he said.
"It was probably great to watch, but it wasn't very nice to play in because it was so open. We didn't feel we actually played that well even though we won 3-1, although the main thing is that we got the job done.
"I think we deserved to get through because of the work we have put in all season and I would like to think Wembley will suit us.
"If we turn up on the day, we have got to be confident."