Simplicity is a variant of Four Seasons that is well-named. Wins are common and you won’t have to work too hard to get them.
The foundations build up, following suit. The rank of the first card played onto any empty foundation pile must match the rank of the card placed on the first foundation in the initial layout. (For example, if the first card placed on a foundation pile is an eight, then eights must also be played onto the other empty foundations.) Building is circular, with Ace following King.
Sometimes you can move multiple cards from one tableau to another, by moving individual cards to other tableaus (especially empty ones) before collecting them all again onto the destination. This can help you empty tableau piles and make more room for new cards from the deck.
Try to avoid leaving cards in the discard pile. It’s okay to leave the “final cards” (the two or three that will go to each foundation last) in the discard pile, but the rest should be played to tableaus or foundations as soon as possible.
When possible, empty a tableau by building its cards onto other tableaus or onto the foundations. Try to keep a couple of tableaus empty most of the time, but no more than a couple.
Play most cards to the foundations as soon as possible. However, sometimes it is worthwhile to leave a card in the tableau, in order to empty another tableau.