How to start building a web application

I'm looking to build a web application and not sure where I should begin or what kind of budget I should be looking at for the development.

I want to build the app with the following capabilities.

Front end

• general public can register/login though a form or by connecting social media account
• * When logged in they get a dashboard where they can see survey's available to them see a schedule for upcoming events they are signed up for
• See points accumulated for participating in events and doing surveys

back end

• managers can search and review data in the user accounts (lookup a name, phone number, # of points the person has, etc.)
• managers can create custom lists of user accounts based upon different attributes
• Ability to create user survey forms or intigrate with LimeSurvey
• Managers email the custom lists with survey links/Links also appear in user dashboard of assigned users
• Ability to assign events to users

This is roughly the idea. There will be more things to add but this is 80% of what is needed. Is there any current apps that can be modified to accomplish something like this or does anyone have a good recommendation for where to get pricing to build this. Any pointers would be appreciated.

Epic visual tool

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