Dear Gitu,
A vague and open-ended conclusion can be that there aren't too many queries or concerns now. However, that's somewhat invalid because if the volume of queries was higher earlier without the help desk, it cannot subside now.
Every initiative needs to be promoted until the point of acceptance. Communication through emails and posters is essential. However, a greater level of promotion is required to create a greater impact. A new system requires a change in habits, which is time-consuming and needs reinforcements initially to be established.
Plan for the Next Three Months
Create a detailed plan for the next three months with Townhalls and focus group meetings. Get all your business leaders to own this promotion. In the first round, get the top leaders to speak to the employees in an open house format or Townhalls. Let the employees hear the top leader talking about it. Let them ask every question related to it.
In 3-4 weeks, arrange for focus group meetings with selected team members who can influence others to act. Send the message across and get them to share why it is helpful.
Identify a SPOC [single point of contact] from each team to anchor the queries initially.
In some months' time, the habits will be formed, and the usage will increase. But you need to actively work for it!
Wish you all the best!