Zazen (sitting meditation) needs to be practiced daily in order to develop the discipline and structure of remaining in the present moment, the place where Zen begins. Here are some suggestions for developing a daily zazen practice.
Try to sit in the morning, as soon as possible after getting up. If you need a beverage or something to eat, that's ok but try not to get involved in the newspaper or TV or your computer, etc. before your zazen, as the relatively "quiet mind" of the night will be broken. Try to sit at more or less at the same time every morning. After some time, you may wish to add a second sitting in the evening.
If you are a beginner, start with 5-10 minutes and slowly extend the time to 25 minutes. You can, of course, begin with 20-25 minutes as well. Get a kitchen timer so that you don't have to continually be looking at the clock. Remain sitting until your time is up, no matter how fidgety you may get. Keeping the body in place is the first hurdle of Zen practice. If you miss a day, come back the next day. Discipline and structure develop slowly. Don't criticize yourself for any lapses. Just come back next time.
If you can sit with the sangha on some mornings, you are encouraged to do so. However, since you will be sitting at home at least some of the time, here are some suggestions for a place to sit:
If possible, keep your sitting area permanent. You can set up a small altar with candle, flowers, incense and even a buddha if you wish. If you don't have a zabuton and zafu or bench, use a straight back chair in which to sit until you can purchase the mat and zafu/bench. (If you sit on a chair, sit on the first third of the chair without leaning back. Keep the same posture as you would on the floor.) Don't rig up your own zafu as you may not be getting the right support. You can use a blanket on which to sit instead of the zabuton but never sit on the floor without some cushioning underneath.
Approach your sitting place with mindfulness and attention. Never rush to your mat. A few moments of preparation to help you be present will allow you to begin zazen in as concentrated a place as possible.
Be patient with yourself. Developing a Zen practice takes time.