So, this could be done in 1 of 2 ways:
1. There would be detailed ballot initiatives that contain full legal proposals, details of their execution, budget, etc. and voters simply vote "yes" or "no" to them.
We see this as referendums and ballot initiatives. When used sparingly for "big" questions, this works well, but when used routinely, it puts a pretty huge burden on voters to be continuously informed.
Take the California ballot this year. There was a ballot initiative about regulating kidney dialysis procedures. If it were the only ballot initiative, I might have had time to research it, discover the motivations around it (is it because of safety, or protectionism for an industry?) the consequences (does it need tighter regulation? do those regulation costs fall on the consumer?) etc.
But, there were like 20 of these things on the ballot. At some point, it becomes actual work to figure out all of them and research them thoroughly enough to know what the consequence of your vote would actually be.
Ideally, you'd have some sort of agent working on your behalf, sifting through the consequences and political motivations, and navigating the 'yes/no' votes in a way that aligns with your ideal outcomes. This is, theoretically, what politicians already do :)
2. Instead of exact legislation, you specify a general intent. Say that you were generally pro-environmentalism. All things being equal, you'd like things to go more towards environmental preservation, ending climate change etc.
Ok, cool, but now there's TONS of room for interpretation. Extreme case, as executor of this mandate, do I have carte blanche to do anything as long as it decreases the carbon footprint? Anything? Induce a famine to reduce usage and consumption of goods?
You'd probably need a more thorough statement of general intent and sentiment. Political parties (outside the weird US system) basically have this. They release a document, usually called a Party Program, which outlines their philosophies and intents.
Theoretically, you're voting for the party and the person you elect is someone who is ideologically dedicated to realizing the intents of the shared Party Program to the best of their ability.
This system works really well when there's a diverse collection of parties with different ideologies, different levels of concrete plans to realize these ideologies, and paths available for such parties to gain legitimate power and sway in the government.
The US 'parties' are missing quite a bit of the above, but I personally think having many parties and fixing our voting systems so such parties can eventually be in congress/the presidency would create a system where issues that people actually care about would be implemented (roughly) in ways they would approve of... at least much moreso than they are now in the US.