Although this Victorian variant looks just like chain stitch, in some contexts it can be much easier to work.
Instead of starting at the base of the chain, start at the top with the small straight stitch. Then bring the thread up at the start of the next stitch, slide it under the first straight stitch, and push it back through the same hole you came up . For the next stitch, slide the needle under the loop you just made and continue until you’ve made all your stitches.
Use it for the same things you would use chain stitch for. I’ve found that for me, curved lines are more difficult using this method, and sometimes closely spaced rows of the stitch are also more difficult. But it’s a nice variant to have in your arsenal.