how to use SignInManager.SignInAsync in blazor web app?

<EditForm  Model="@_model" OnValidSubmit="OnValidSubmit">
    <DataAnnotationsValidator />
    <ForumAlert AlertModel="_alert" />
    <MudCardContent>
        <MudTextField Label="First name" HelperText="Max. 8 characters"
                      @bind-Value="_model.UserName" For="@(() => _model.UserName)" />
        <MudTextField Label="Password" HelperText="Choose a strong password" Class="mt-3"
                      @bind-Value="_model.Password" For="@(() => _model.Password)" InputType="InputType.Password" />
    </MudCardContent>
    <MudCardActions>
        <MudButton ButtonType="ButtonType.Submit" Variant="Variant.Filled" Color="Color.Primary" Class="ml-auto">Zaloguj się</MudButton>
    </MudCardActions>
</EditForm>

@code{
    private async Task OnValidSubmit(EditContext context)
    {
        var model = (LoginFormModel)context.Model;
        var user = await _userManager.FindByNameAsync(model.UserName);
        if (user != null)
        {
            //var principal = new ClaimsPrincipal(new ClaimsIdentity(null, "Basic"));
            //await _httpContextAccessor.HttpContext.SignInAsync(principal);
            await _signInManager.SignInAsync(user, true);
            _navigationManager.NavigateTo("/");
        }
        else
        {
            _alert.Warning("User not found");
        }
    }
}