When you click a card the game makes the best simple move it can. I'd like to see a way to opt out of this. I've been playing MS Freecell for years and It doesn't do this. I like to make all the moves myself. I've got 1680 perfect games on MS.
You know, you can always click on the card you want to move then, while holding the left mouse button down, drag the card to where you want it to go, instead of just clicking it and accepting where it puts itself. Also, if you have a stack of cards you want to move, you can click on the top card, hold the left mouse button down, and drag them all where you want them to go. Congratulations on all those perfect games!
Yes, @Sage is right. Dragging is the way to control the move yourself. Note that cards my move on their own if you hover in thought too long (as we assume you are waiting for us to move a card out of the way). Just move away without letting go of the card and everything will be put back.