With a Vanguard retirement date fund or a lifestrategy fund you do not have to monitor it, do anything.
You make the initial decision of which fund to be in, setup the recurring payment in to it, then maybe look at it once a year, aiming to increase the amount you pay in. The less you look at it the better, as then you do not get scared by drops in value due to market fluctuations.
These off the shelf portfolios are really easy to use. SIPP is the wrapper around it. The SIPP is not fully functional - it is a simple SIPP as you cannot have property in it, or anything fancy... it is just a pension wrapper which the provider (platform) manages, providing the admin system for taking in payments, obtaining tax relief, and buying units in the investment.
The platform also arranged access at retirement - Vanguard Investor does flexi-access drawdown using a process called UFPLS which enables a payment to be made to you where 25% is tax free and 75% is taxable. Don't worry about that now though, over many years things can change, admin systems will improve and taxes will definitely change.
Focus on now. Set something up which is simple and low cost. A Vanguard Investor SIPP with a LifeStrategy fund or a Retirement Date fund in is fine. Just be aware that the retirement date fund will change the equity percentage as you get closer to retirement.