How to prepare for german volume training
Be sure that you want to grow muscle primarily, pick the right exercises to do for 10x10 and start with low load. If you have not perfected form yet, seriously consider doing that first, before ingraining bad form by doing a lot of repetitions when on GVT.
Check if you picked the right method for your goal
It is important that you check whether 10 sets by 10 repetitions, which is the method at the heart of GVT, is the right method to reach your goals. If you your aim is to gain the most muscle mass in the shortest amount of time and you do not care about endurance, strength or explosiveness, german volume training is the correct pick based on my experience. However I do not think it is a program for beginners.
I personally would not recommend 10 x 10 as a program for beginners because I personally think the primary goal for beginners should be to either lose weight, if they are overweight, or to build a very strong base which adresses endurance, strength and explosiveness. I personally do not feel like that GVT is the best way to adress that.
If you have played sports in your teenage years and were somewhat sucessful in that period whilst well built, you have that base. Fire ahead with this program.
If you have missed the opportunity in your teenage years by being sedate, build that base first with circuit training, kettlebells, push ups and pull ups before going for GVT with a barbell and or getting yourself in the machines at your local gym.
Also GVT is calculated from your one repetition maximum. Beginners usually first have to figure out good technique before moving into one repetition maximum tests. This is usually best done with low rep ranges which are performed with maximum focus on correct execution. Weightlifting trainers usually use a rep range of 1 - 4 for this kind of technique fine tuning.
Pick the right program for your goals
As the basis of German Volume Training is 10x10 for anything you may possibly like, there are several templates out there which use this guideline. Depending on their structure they will achieve different things. Just because it says "German Volume Training" it does not necessarily mean, that you will reach your own personal goals with it.
Therefore check whether the exercises of the template of your choice actually match your goal. If you want big arms, make sure there some biceps curls in there.
If you want big legs, leg presses and curs will be to your benefit.
If you would like a big back, deadlifts are recommended. Barbell work and compound lifts are always a good pick to built an overall impressive physique while isolated machine work will help you to pump a specific muscle up to the maximum.
Start low and increase
The GVT template I used recommended to work from 60% of your one rep max. I started with that and I was not able to finsih the repetitions and sets. From broke down and I did not get the desired results.
I dialed back to 40% of one repetition maximum and worked my way back up from there. Believe, if done correctly, GVT is no walk in the park.
Pay extra attention to form
In each session you will perform 100 repetitions of a particular movement. This will ingrain the movement pattern into your routine and leave marks for execution in future. Grind down on form before you do GVT and then get those 100 reps a day in to manifest the correct way of doing it. If you have shortcomings in your form and run GVT it is very likely that it will be harder to get rid of those after you have completed the program.