I agree with the last two posts. I think you're in way over your head and I think most of the advice above (except the last two posts) isn't very good advice. Pricing jobs by the hour is always a bad idea. You should be pricing jobs - by the job. Similarly, pricing ANYTHING with some generic "by the sq. ft.", "by the yard", "by the linear ft.", "by the zone" (as with irrigation systems), or "by the fixture" (as some people do with landscape lighting systems" is always a bad way to bid work. Why? Because every job is different. Access is different. Drive time to and from the jobsite is different. Materials needed are different. One lawn may need to be heavily amended with a lot of new soil another may need only a little. Etc. Every landscaping, paver patio, irrigation, lighting job is totally different from one to another.
Your best bet is to start doing jobs like this SMALL. Then you'll learn what materials and time was needed for the job. Then take on a little larger one. Then a little larger, and so on. Start small, so you can make mistakes and it won't cost you very much if you screw up on your total bid price. Then, as you learn more, you'll learn to think of everything that is needed for every job. You'll be able to accurately predict exactly what materials you'll need, exactly how many hours it will take, exactly what other factors to consider (drive time, access to the work area, mark-up, etc.) and then you'll be set to take on jobs like this.