(English) It is important that a head coach define their expectations for their assistant coaches and players. Assistant coaches ought to be given meaningful roles (within their skill and expertise).

Roles that an assistant coach may perform are:

scouting upcoming opponents;
complementing the coach’s areas of strength (e.g. a head coach may be particularly good at teaching “point guard play” and an assistant may be a good “post coach”);
arranging logistics in regards to practice (e.g. sourcing venues, setting up for practice, communicating with players);focusing on particular areas during a game (e.g. one assistant coach may focus on an opponent’s offence and another focuses on the opponent’s defence) and reporting information to the head coach. Some head coaches will simply ask for information and others will require the assistant coach to make recommendations;
keeping statistics during games;
conducting individual or small group sessions with players;
keeping in touch with players and reporting to the head coach if there is dissatisfaction or unhappiness.

Whatever roles a head coach wants an assistant to perform need to be clearly defined, as does the level of responsibility that the assistant coach has.

For example, if an assistant coach is scouting upcoming opponents, will they present that information to the team? Do they need to discuss specific recommendations with the head coach first?

The level of responsibility that an assistant coach has will depend both upon their skills and experience and also the head coach’s preference.

In determining roles, the head coach should consider that:

the less they (the head coach) delegate, the more the head coach has to do;
assistant coaches with low levels of responsibility may become disenchanted with the role and look to move;
assistant coaches may have expectations of what the role will involve which may differ from what the head coach wants. If any difference in expectations is allowed to continue it is likely that neither the head coach nor the assistant coach will be happy.

It may not be possible for the head coach to exhaustively define everything they want from the assistant coach and instead (like any relationship) it may evolve over time. Some considerations that the head coach can address:

If possible, meet with assistants prior to practice (or at least provide them with a copy of the practice plan) so that they understand the objectives for practice and what activities are to be done. Involving assistant coaches in planning practice increases their understanding of what the head coach wants to achieve;
Having assistant coaches present parts of practice enables the head coach to observe players from a different perspective. It will also increase the “credibility” of the assistant coach with the players;
Debrief with assistant coaches following practice and games. Seek their opinion, do not just present your own opinion;
Be honest. If you were unhappy that an assistant coach communicated a defensive switch directly to players during the game, address that with the assistant coach. Be precise – are you unhappy because you want the assistant coach to communicate suggestions to you rather than directly to players? Or, are you happy for them to communicate directly to players but you believe that particular decision was a mistake?
Seek opinions from the assistant coaches and be prepared to consider something that they suggest which is different to your own opinion. When assistant coaches believe that their opinions are valued by the head coach, they will more willingly contribute. Ultimately, the head coach makes the decisions and assistant coaches must understand that they will make some suggestions that are not accepted by the head coach.