Help required in Database Counter Display

Hello Wix Experts :
First of all , my knowledge about java script coding and publishing in the web site is so poor , I created a website by using wix templates , and published it few days ago , this web site contains several database collections with different categories , which is collecting data by form input from website members ,
I am facing two major issues to operate this website smoothly .
The first issue is ( displaying database counter for different categories in individual text box , to give the website visitors indication about how many profiles in each category )
in details i will give example to one of the database collection with related sub categories My database name is ( Engineering ) and the column name which i want to count is ( Sub-Category ) under this column i have different types of engineering , for example ( Electrical Engineering , Mechanical Engineering , … )
Now my request is to help me and provide a code that i will copy and past to get the result of this counter in a text box which will just show how many profiles in the page , for the above example and i will change the database name and sub-category name along with the text box reference . and please advice what i have to do to display counter of all sub categories in the main page ?
The second issue is to receive a notification every time there is new submission in my database , i did the user input form by using wix user input elements , and i didn’t find setting option to get such notification after form submission .
Sorry for this long story , but i tried to make my issue clear , as possible .
Thank you in advance

This is screen shoot from my page , i want to add the counter under each one .

There is some code needed to get created to make this work. Especially your second issue is advanced. The first one you can get from going to the API docs and look for Data and under that Query and the totalCount parameter.

Thank you Andreas for your reply .
I can live with the second issue, it will not affect the webste mechanism,
but regarding to your advice for the API cods ,
i did checked that code and i failed to make it work , the reason is me NOT the code .
that’s why i requested if possible one of wix experts can provide to me a complete code for my example. wich will do the qury & count function then it will show the result in the text box. and i will change in this code for different datasets categories