You have read several explanations of the mechanics of sealing and they are accurate. However, implied in your question is whether you were going to be left out or somehow disenfranchised because of your doubts. I wouldn't worry about it. There is time. You will be just fine. Doubt is just a manifestation of lack of faith and we all suffer from it from time to time. You are in good company. The question all of us have to answer is how to get beyond that point.
If I may, faith is found in living the principles of the gospel. It is in practicing true principles that we discover their value and thus gain a testimony. If you want to gain a testimony of tithing, pay it. The same goes for prayer or reading scripture or any other principle of the gospel. You get a testimony by doing it. With your testimony of these things comes the faith needed to make the commitments you are are hesitant about. Most importantly though is just take it easy. Do these things one at a time or as you feel comfortable. The timing is not as important as the doing.
You will find that as you get a testimony you will want to do more. Sometimes it is just the first few steps that seem like climbing a mountain. If your heart is right, that is you don't try to live a worldly life too, and you keep at it, things will take on a life of their own and in no time you will be anxious to get on with it. The process of obtaining a testimony is like visiting your dearest old friend. You hate to be separated and you want to be with them and do more things with them. Soon, your testimony becomes like your family and you can't imagine what it would be like with out it. At that point going to the temple is like going to your favorite grandparents house - you can't wait. Your current sense of feeling ill at ease will be replaced with a sense of peace and fulfillment like you may never have felt before.