These political groups are formed by members elected by national voters. A group can be formed as long as they have at least 25 members from at least one quarter of EU countries. They're pretty much analogous to a party, they work in broadly the same way. In the Image above they're broadly organised from Left to Right politically:

The LEFT group is, well, pretty left. They include Communists and Socialists, and in their own way can be a bit eurosceptic, although they typically want to reform or replace the EU rather than just disbanding it.

The GREENS are also pretty left, with a focus on Climate, Animal Rights, Income Equality, Feminism, that sort of thing. They are generally pro-Europe.

The S&D group are center left. Members tend to be from say, the Labour party of various countries. They want things like fairer employment and more regulated market. They were the largest party in the EU until 1999, now the second largest.

RENEW are Center, pretty Liberal (in the Phil Ochs sense). They're pro-business and want a strong economy, but they at least talk up things like civil rights and social welfare (I don't know enough about them to judge how well they do in practise). They're very pro-EU, and have billed themselves as 'the Pro-European political group'.

The EPP are center-right, pretty conservative. Lots of 'Christian Democratic' representation. Neoliberal, want more defence spending, pro-Europe, pro-Ukraine. They say they're focused on the climate, but the Greens say that that's a lie. They've been the biggest group since 1999.

The ECR calls itself center-right (but is really a bit right-er), and 'soft-eurosceptic'. This Eurosceptism is their main thing: They support the idea of the EU, so they say, but they want to prevent it from going 'too far', with too much oversight, integration, and immigration. Some members are your standard conservative types, some are far-right.

The ID group is far-right. They don't like the EU, and are opposed to it interfering with the 'sovereignity' of States. Anti-immigration, anti-'islamisation', pro-nationalism.

Nonaligned (technically 'non-inscrits') are just that - they haven't joined with any of the above blocs.

These projected results broadly show increased support for the right over the left, but more sharply show gains for the Eurosceptic ID and Non-Inscrits (who often are Eurosceptic, but not always and I don't actually know the individual cases here) at the expense of the pro-EU Greens and Renew. So it doesn't look great for fans of the European Left.

Traditionally, the EU has been governed by an informal coalition of the two largest groups/parties, centre-right EPP and centre-left S&D, both being pro-EU. After the last election where they underperformed, they were joined by the third largest group, centrist, pro-EU Renew.

This election, pro-EU groups collectively have lost a lot of seats while right-wing EU-sceptic groups gained seats. The most radical of these groups, ID, made the biggest gains. This will make coalition building and therefore governing way more complicated.

European parties are alliances of national parties from various member states. Those representatives elected to the European Parliament for the national parties form so called groups. Typically, these groups correspond to the European parties. Usually, it makes more sense to talk about the groups rather than the parties.