plugin development in WordPress

Hi! Finally, here are the details about our need for customization of Crocoblock Jetappointemnets, so it fits our gym appointment system. Login in staging here: [login to view URL] Important : It needs to be absolutely in jet appointments. We have started working like this and it needs to stay in this. We don't want jet engine. Current functioning : We have a system that will use the following status as follow : Pending : User registered for the course/appointment, but the course hasn't happen yet Confirmed : A trainer at the gym manually confirmed the user's presence Cancelled : The user cancelled is appointement in advance, in time Failed : User was registered for course, but did not show up. A trainer (admin) manually change status to "fail" User see in their account what they have under each status above. Since the group course are will be inside more complex programs, we use learndash as a pay wall for members. As such, they can reserve their course inside a learn dash "step" : [login to view URL] Upon registering, they receive an email and the email contains the cancel link only. Our needs : 1. Ability to manually add appointments in the past (for walk-in appointments). This is very important. Right now, it seems impossible in jet appointmeents to add people after a date has passed. But it is very important for us because some people show up at courses and we need to be able to add them after, and confirm them after (because how we use the status). 2. Customize the appointment views in admin [login to view URL] In the LIST VIEW: [login to view URL] and order by time slot (see all people in the Wednesday february course at 18h30 TOGHETHER for exemple). Right now we can order by date, but we cannot make sure all the same time slots are toghether. It's messy. So we need that somehow, either with like two or three sorting levels. [login to view URL] need the filters in place to STAY if the page is refreshed, until manually "reset". Right now we have to re-filter each time we do a move or confirm an appointment and it's a pain 3. We need to be able to BULK select and change the status of many appointments at the same time. A use case for this is confirming presence of the 12 course attendees at the same time. 4. We need to be able to have a button to quicklu confirm / change status of one single appointment too. so a button in a column somehow. Right now the "status" coluumn is not clickable for example... In the CALENDAR VIEW: 1. Instead of seeing the time first in a calendar "cell" we need to see the name of attendees some how. Improving the view to display BOTH the time and the name would be great. 2. In those calendar cell, appointments needs to be sorted by timeslot. So let's say all the 8:00 AM are togheter in first, followed by all the 11:00 AM, etc. In the TIMELINE VIEW 1. Ability choose from wich hour to wich hour I want in view. And make it persistent if I refresh. So let's say for the evening shift I just look at the timeline between 6:00 PM and 9:00PM. 2. In the "timeline" cells, show the NAME of attendee, not the email In all those views, one thing is very important : when we choose list, calendar or timeline, I would like this choice to STAY during an admin session if I refresh the page. Right now if I'm in calendar and refresh, I go back to list and lose any filtering option. Really unpractical. 3. Be able to EXPORT the appointment data in csv or excel file for admin needs. Note : Only experienced Freelancer can applied for this job