Before starting to paint with oil, remove the tubes of acrylic paint.
In the painting courses I teach, I experience time and again that
acrylic and oil paint tubes are confused.

Oil paint is very economical. Just use very little for your palette.
You can always add more.
Avoid picking up paint with your brush straight from the tube.
Sometimes this works, but at one point in time the paint is contaminated,
rendering useless a tube which would have lasted years and for many more paintings.
In the shopping list you might have missed something like mediums,
something to thin oil paint with.
Mediums have the purpose to affect the drying property of paints.
Thus you do not yet know which medium is needed or which you believe to be needed.
For glazing you definitely do not need a medium.
Later on I will give you special advice for the technique described here.

Now, again pick up some paint with your brush.
The paint should never come up to the brush handle.
If too much paint is taken up by the brush,
you might not be able to apply it to the section intended.
As already mentioned, oil paint is very economical.
Scumble it in such a manner as to release all the paint taken up by the brush.
If, subsequently, you can pick up globs of paint like from a palette, you (still) applied too much.

If you judge the shade not to be sufficiently intense,
keep in mind other likely painting stages to follow.
Now you scumble every area with the respective shade it is to take on.
Remember, the gradual build-up and the texture of the underpainting shine through.
Contrast should only be sharpened during the next scumble.
Generally speaking, do not yet bother too much with details.