"Well" means regularly, evenly, so that the consistency of the cream is well homogeneous, and it is not so easy as that.
What is the problem?
First of all, it's a question of temperature: gelatin is soluble at 37°C, so it is imperative that your cream is above that temperature, otherwise it will not dissolve.
Well it is often the case in fact, we heat a first mixture for a cooking (like custard) and then we incorporate the gelatin, but it is necessary to remember it anyway.
Then it's a question of structure, the gelatin is in a different form from your cream, which is rather liquid.
The gelatin is either sheets (of 2 gr) or powder, and incorporating it into the structure of your future cream involves some precautions.
Sheets and powder
If you use
gelatin sheets, you will first have to soften them for 5 minutes in a bowl of cold water, then wring them out (squeeze them in your hand over the sink), pour them into your hot cream and immediately mix them well, we say "disperse", with a whisk for example or with a maryse.
If you use powdered gelatin, it's easier: you pour the powder directly into your hot cream, whisking at the same time to disperse immediately.
Is this enough?
In theory yes, if you did it quickly and well, no problem for your cream.
In practice, you may have some concerns about the homogeneity of your cream, with some areas a little more set than others, especially if your cream was a little low in temperature (< 50°C).
Is there a way to ensure a perfect dispersion?
Yes, just give your cream a quick blast with a
mixer (less than 10 seconds) once the gelatin is incorporated.
Not only will you disperse the gelatin perfectly, but you will also smooth your cream, which will be even smoother once it has cooled.
This dispersal of gelatin, and of gelifiers in general, in a mixer is a common practice among professional pastry chefs.
Don't hesitate to use this professional trick to obtain very nice and creamy creams at home.
To sum up: To properly incorporate a gelling agent into a cream, you must make it "hot cream" and then disperse it with a mixer for a homogeneous result.