Dinys Monvoisin Thanks for the feedback. That's an excellent question! If someone has just joined your company, this is a particularly great time to reach out to them to offer assistance without it seeming to infer anything about their capability. Offer yourself as a resource as a fellow teammate in case they have any questions about getting up and running in your team or within the organization as a whole. No matter how capable a person is, entering a new environment comes with a lot of uncertainty, so even if they don't take you up on the offer, you will create a lot of goodwill by showing that you are interested in helping them succeed in their new role. This will also give you a nice segue into keeping that person posted about company news or even interesting things you learn that are relevant to the project.
If it is clear that they are having trouble within the scope of your team projects, offering help in terms of "hey, you really seem to be doing great so far. But I know every team is different and I don't know about you, but when I started on the team, this confused me. This is how they approach things here." will make it seem non-confrontational and more of an insider tip.
Good of you to identify that someone on the team might need a little assist. It is this type of observational skill that is needed to be an excellent teammate!