Start with an even number of chains.
SC in the 2nd chain from the hook. CH 1 and skip the next chain. SC into the next CH space. Chain one and skip one and SC again. Continue this pattern all the way across.
Your last stitch in the final chain should be a SC. CH 1 and turn. SC into the SC you just made on the row below. CH 1, skip the chain space, SC into the SC. repeat the sequence all the way across. Ending again with a SC in the last SC. CH 1 and turn.