The function of the aorist tense in Quenya most closely resembles the simple present form in English: “the man eats, I eat”, i nér mate, matin. It is not, strictly speaking, tied to the present moment, however. More accurately the Quenya aorist is not tied to any particular time at all. Although it is often used to refer to the present, it is also used for habitual actions or other statements which are true independent of time. As Tolkien described it Quendian & Common Eldarin Verbal Structure (EVS1) from the late 1940s:

The basic verbal noun in Quenya is the gerund, formed from the verb stem using the suffix -ie, roughly equivalent to English “-ing”. This English suffix is also used to form the active participle, but Quenya has a different suffix for that. Compare “eating is good” matie mára (ná) [gerund] vs. “the eating man” i matila nér [active participle].

Yalo Atani utúvier sa Iþil *hetya menelwa hrondo ná xaraner lelya tanna. Yá hindo nén mo kimne imbi ammelde parmanyar i *nyarnon "Lenda Iþilenna" ló Jules Verne, yasse verke atalli lende Iþilenna *hatilesse hataina haura *hatarotsello. Epe *queanyelli Atan naitie anyane Iþil i *kúmakiryanen Apollo-11.

Koranarelli palla i kúmakirya Apollo-13 ata rinke anyaitas, mal *verehtale to i kirya tenge i kiryamor lá lertaner unta Ráno palmenna, ar mauyane ten *osta Ráno *katya palme tenna lertaner *menu mardar. *Xétanente *lúmestar tolto morniesse Iþilo leosse ya tankave rúkima né.

Part 60 is just a tiny bridge entry introducing verb tenses, not worth posting.

The simple infinitive in Quenya is just the uninflected aorist form of the verb: cen- → cene “to see”. Tolkien described the infinitive at length in Common Eldarin: Verb Structure composed in the early 1950s:

In ᴹQ. Fíriel’s Song from the 1930s there are signs of a “stative” verb inflection; I don’t know who coined this term for the Quenya construction. This song has nouns and adjectives with the verb “to be” directly attached in the form of the suffix -ie (LR/72):

A “copula” is a linguistic term for a small linking word connecting a subject to a predicative expression. In English, the copula is the verb “to be”: “Elrond is a man; Elrond is old”. In Quenya, the verb ná- may be used as a copula, but it is often optional. It is perfectly normal in Quenya to put the predicative expression immediately after the subject without an joining word at all: Elerondo nér; Elerondo yára.

Quenya verbs show a number of irregularities and unexpected behaviors, especially in the past and present tenses. However, there are some verbs that, because of phonological peculiarities or their foundational natures, are more irregular than usual. Tolkien mentioned this in the Quenya Verbal System from 1948: