How does several request http make in order which are in a foreach-loop?

Question

My code is the below:

automaticAssignment() {
    this.model.selectedSignals.sort((a, b) => a.senal.localeCompare(b.senal));

    this.model.selectedSignals.forEach(signal => {
      if (signal.status === Asignacion.ASIGNADA || signal.status === Asignacion.AUTO_YA_ASIGNADA) {
        this.messageService.add({
          severity: 'warn',
          summary: i18next.t("assignment:automatic_assignment"),
          detail: i18next.t("assignment:signal_already_assigned", { signal: signal.senal })
        });
        signal.status = Asignacion.AUTO_YA_ASIGNADA;
      } else {
        const channelAvailable = this.model.channelList.find((channelAux => channelAux.tipoIO === signal.tipo && !channelAux.bloqueado && !channelAux.senalId));
        if (channelAvailable) {
          this.http.put<any>(`${this.signalUrl}/${this.model.selectedProject.id}/assign`, null, {
            params: new HttpParams()
              .append('plcId', channelAvailable.id.toString())
              .append('signalId', signal.id.toString())
              .append('value', "true"),
          }).pipe(
               tap(// Code which change the parameter senalId of channel
           )).subscribe(() => {});
        } else {
          this.messageService.add({
            severity: 'error',
            summary: i18next.t("assignment:automatic_assignment"),
            detail: i18next.t("assignment:no_available_channel", { signal: signal.senal }),
          });
          signal.status = Asignacion.AUTO_NO_CANAL;
        }
      }
    });
    this.model.selectedChannels = [];
  }

The problem I have is that if the array selectedSignals has several channels, the http request always have the same parameter plcId because the http-calls are asynchronous. I need that requests execute the code which is in the subscribe in sequence in order to the find method returns different channels.

How can I make this? Maybe should I use an array to join all the request and use concat()?

Thank you in advance,