This is exactly the worksheet I used ( I think in 2013) to get into a regular habit of meditation. I wrote down entries in a notebook with a small square at the beginning. And each day as I completed my meditation, I checked off a box. I think I may have missed a day or so, but in those cases also, I sat down for a little time at least, like a few seconds to a minute and that got me a check. The sense of accomplishment at the end of 40 days helped me take on another 40 days and so on gradually I built up my habit which I have maintained for 3 years now.
And here is another one that I used recently (for something else). This one is pocket-sized, so it can even fit inside a wallet. Finish one set of 30 days, and then start another one. Before you know it, you will have created the habit you will need for a lifetime's practice.